CODEWITHSUNDEEP
arraysocaml
asdfasdfwe
asdfasdfwe

Reputation: 71

OCaml - Modify array values

I want to modify an existing array with this function but for a reason I don't understand once I apply the function to the array the values do not change. What am i missing ?

Thanks in advance

let test v (a,b) = 
for i=a to b do
    if ((Array.get v i)>(Array.get v i+1)) then
        let tmp = (Array.get v i) in
            v.(i)<-(Array.get v i+1); 
            v.(i+1)<-tmp;           
done;;

Upvotes: 0

Views: 2945

Answers (2)

camlspotter
camlspotter

Reputation: 9030

The best practice is to put white spaces at function applications including binary operators.

Many newcomers tend to misunderstand

Array.get v i+1

as Array.get v (i+1) but if it is written like

Array.get v i + 1

then the chance of mistake should go much lower.

Upvotes: 4

Pierre G.
Pierre G.

Reputation: 4425

The error is in Array.get v i+1 : this infers that v is an int array, and that you add 1 and make the condition always false. Just put i+1 in parenthesis : v will be an array of any type, and it will solve your issue.

let test v (a,b) = 
for i=a to b do
    if Array.get v i > Array.get v (i+1) then
        let tmp = (Array.get v i) in
            v.(i)<-(Array.get v (i+1)); 
            v.(i+1)<-tmp;           
done;;

You could have written using v.(i) > v.(i+1).

Upvotes: 3

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